Science Buddies: "Ask an Expert"

In my science project (https://www.sciencebuddies.org/science- ... #procedure), I'm having trouble understanding some of the instructions. In steps 4 and a little bit of 5 is where I'm am having this trouble. I don't understand where to get the conversion factor. Do I use both the height scaling factor and the width scaling factor at the same time? Do I do it separately? If there are any further questions about the problem I'm having, please ask.

Thanks!

Hi Floringr,

Welcome to the forums.

The "height conversion factor" and the "width conversion factor" are the "height scaling factor" and the "width scaling factor" in equations 7 and 8, respectively.

You do need to apply both the height scaling factor and the width scaling factor at the same time. See the example in Figure 13, where the shadow length is decomposed into height (h) and width (w). So you apply height scaling factor to h and the width scaling factor to w to get the correct scaling before you compute the shadow length.

I hope this explanation help.

JChang

So I would take the height of a line I measured, 1.447 cm for example, and would I multiply it by the height scaling factor I got for that image, 1.67325, which would show me that the line I measured is actually 2.42119 km in height?

Hi Floringr,

Yes, that is the idea.

For the data you provided in your post under the Physical Science forum, the height scaling factor and the width scaling factor are almost the same. However, for some users, both factors might be quite different, depending on the printer or computer screen used, which is why different scaling factors are used for height and width, respectively. Furthermore, the length (L) of interest might not be horizontal or vertical (see the shadow length L example in Figure 13). So if the length you want to measure is slanted, it needs to be decomposed into the height component (h) and the width component (w) so that the corresponding scaling factor can be applied before you recompute the actual length.

JChang

Just to make sure I'm doing this right, would this be a correct example of my work?

Crater 2 Image 1- Diameter
Line Height= 0.025 cm
Line Width= 1.524 cm
Convert to kilometers by multiplying by corresponding conversion factor...
Line Height= 0.116142 km
Line Width= 7.080032 km
L^2 = h^2 + w^2
L = 7.08098 km

So my final answer would be that Crater 2 from Image 1 has a diameter of 7.08098 km?

Thank you for all of your help!

Hi Floringr,

Yes, based on the numbers you provided, you have followed the procedure correctly and your calculation is correct.

JChang