1. Elevate one side of the air track (place a flat object under the right air track leg, see Figure 2 below). The glider will accelerate due to gravity.

2. Place the first photogate ("start") in a position that will allow you to gently push the glider. The "start" photogate will be in the same position, x₀, during the experiment. Place the second photogate (the "stop" one) close to the first one. You will move the second one to obtain different distances. Make sure, that the photogates are mounted high enough to allow the glider freely go through both of them.

3. Connect the photogates to the electronic stop clock: the first one to the start slot, and the second one to the stop slot, as shown in the picture (Figure 3).

4. Turn on the stop clock (Figure 4). It should show 00.0000 s (Figure 5). If it does not, then try the restart button. The photogates measure the time that the glider needs to travel the distance between them. When the glider passes through the first photogate, the clock starts measuring time; it stops when the glider passes through the second one. If the photogates operate in a different mode, try to switch the MODE button.

5. Watch the video (Figure 6)

Experimental Procedure

1. When the air track is ready, you can collect the data. Release the glider. Write down position x₁ of the second photogate and calculate the distance d₁ = x₁ - x₀. Move the second photogate to the left or right and note down x₂, then calculate d₂ = x₂ - x₀. Repeat.

2. Collect at least 20 data points (time t_i, distance d_i)

3. Plot your data in Desmos. Find the best fit line using the regression tool.

4. Send a link to the graph through Brightspace.