Syrup
Common names: Golden syrup, corn syrup, honey
Properties keywords: Newtonian, viscous, liquid
Analogue keywords: silicate melt
General information: Syrup is a solution of sugar and water. There are a variety of types of sugar (e.g. glucose, sucrose) but the corresponding syrups are similar enough to be considered together. It is a very common material in analogue experiments because it is readily available, low cost, easy to clean (water soluble) and non-toxic (it is edible).
Properties
For the conditions of most experiments, syrup is a simple Newtonian liquid, which means that the viscosity does not vary with shear rate. However the viscosity is strongly affected by water content (lower viscosity for higher water contents) and temperature (lower viscosity for higher temperature). Also at sufficiently high shear rates syrup is viscoelastic (e.g., Yamamoto et al., 2008).
Syrup density decreases with increasing water content, and to a lesser extent temperature. At normal room conditions, undiluted commercial syrups such as Tate & Lyle Golden Syrup typically have a density of 1.4 x 103 kg m-3. The lower limit for dilute syrup is the density of water (1.0 x 103 kg m-3).
Surface tension has been measured to be 0.08 N/m in both Golden Syrup (Llewelin et al., 2002) and an example of corn syrup (Rust and Manga, 2002). This is similar to water (0.07N/m) and so surface tension is not strongly affected by water content for a wide range of syrups. [Note: The surface tension of water-diluted syrup should not be calculated by multiplying the non diluted syrup surface tension by the fraction of pure syrup in the syrup-water mixture as appears to have been done in Sumner et al (2005).] However, low-water (high viscosity) syrups can have substantially higher surface tension (e.g., Yamamoto et al., 2008)
Syrup is transparent (e.g., Cargill Glucose 01132) or translucent (e.g, golden-brown Tate &Lyle Golden Syrup). The darker syrups have been caramelized by heating.
Figure 1. Rheology of Tate & Lyle Golden Syrup and Golden Syrup – water mixtures as a function of temperature measured with a concentric cylinder rheometer. (a) Viscosity of pure Golden syrup as a function of temperature. (b, c, d) Stress versus strain rate data at 12 °C for pure Golden Syrup (a; best Newtonian fit: 210 Pa s), 90% syrup + 10% water (c; best Newtonian fit: 4.80 Pa s), 60% syrup + 40% water (d; best Newtonian fit: 0.00420 Pa s). After Beckett et al (2011).
Note that these and other measurements indicated that Golden Syrup batches delivered to the University of Bristol are not identical in viscosity, possibly due to variations in water content of the delivered syrup.
Applications
Syrup is an excellent analogue for viscous Newtonian silicate melt and has been used in many experiments (some of which are listed below) to study a range of flows of magma from magma chambers, conduits (including vesiculation), splatter, lava flows and domes. With sufficiently low water content and sufficiently high shear rate, syrup becomes viscoelastic and can be used as an analogue for the fragmentation of silicate melt.
Solid particles can be stirred into syrup to generate suspensions that are analogues for crystal-bearing magmas. Examples include rice, seeds and sugar crystals. Non-dilute suspensions are shear-thinning (non-Newtonian).
Limitations and tips for use
The temperature of syrup during an experiment should be measured regularly because even typical daily variations in room temperature can have marked effects on viscosity.
Users should be aware that the surface of syrup can develop a more viscous skin by losing water to the surrounding air (or can absorb water from the air if it is extremely humid).
Yeast and other organisms can grow in dilute syrups.
Viscous syrups are metastable at room temperature and will eventually crystallize which can significantly affect the syrup properties.
References
Bagdassarov N, Pinkerton H (2004) Transient phenomena in vesicular lava flows based on laboratory experiments with analogue materials. Journal of Volcanology and Geothermal Research, 132: 115–136
Baker, D. R., Dalpé, C., and Poirier, G., (2004) The viscosities of foods as analogues for silicate melts: Journal of Geoscience Education, 52: 363-367
Beckett FM, Mader HM, Phillips JC, Rust AC, Witham F (2011) An experimental study of low, Reynolds number exchange flow of two Newtonian fluids in a vertical pipe, Journal of Fluid Mechanics, 682: 652-670.
Castruccio A, Rust AC, Sparks RSJ (2010) Rheology of crystal-bearing lavas and their dynamics using analogue gravity currents, Earth and Planetary Science Letters 297: 471-480.
Hammer J, Manga M, Cashman KV (1998) Non-equilibrium and unsteady fluid degassing during slow decompression. Geophysical Research Letters 25: 4565-4568
Hoover SR, Cashman KV, Manga M (2001) The yield strength of subliquidus basalts — experimental results, Journal of Volcanology and Geothermal Research, 107: 1-18
Kervyn M, Ernst GGJ, Van Wyk de Vries B, Matthieu L and Jacobs P, (2009) Volcano load control on dyke propagation and vent distribution: insights from analogue modelling. Journal of Geophysical Research, 114, 26pp.
Llewellin EW, Mader HM, Wilson SDR (2002) The rheology of a bubbly liquid, Proceedings of the Royal Society A, 458: 987-1016
Lu CY, Jeng FS, Chang KJ, Tian WT (1998) Impact of basement high on the structure and kinematics of the western Taiwan thrust wedge: insights from sandbox models, Terre. Atmos. Oceanic Sci. 9: 533-550
Mathieu L, Van Wyk de Vries B, Holohan EP and Troll VR, (2008) Dykes, cups, saucers and sills: analogue experiments on magma intrusion into brittle rocks. Earth and Planetary Science Letters, 271: 1-13
Namiki A, Manga M (2008) Transition between fragmentation and permeable outgassing of low viscosity magmas. J Volcanology and Geothermal Research 169: 48–60
Rust AC, Manga M. (2002) Effects of bubble deformation on the viscosity of dilute suspensions. J. Non-Newton. Fluid Mech.104: 53–63
Schellart W, (2011) Rheology and density of glucose syrup and honey: Determining their suitability for usage in analogue and fluid dynamic models of geological processes, Journal of Structural Geology, 33: 1079-1088
Soule SA, Cashman KV (2005) Shear rate dependence of the pahoehoe-to-‘a’a transition; analogue experiments. Geology, 33: 361-364
Sumner JM, Blake S, Matela RJ, Wolff JA (2005) Spatter. Journal of Volcanology and Geothermal Research 142: 49-65
Van Wyk de Vries B, Matela R (1998) Styles of volcano-induced deformation: numerical models of substratum flexure, spreading and extrusion. Journal of Volcanology and Geothermal Research 81: 1-18