Step 1: Start Powerpoint2007 (similar to other versions), then delete all the text boxes in the opened PPT document, then right-click the blank position of the slide and select "Set Background Format" to open the "Fill" branch of the "Set Background Format" dialog box (as shown in figure 1), and set the background color of the slide according to your own preferences; Finally, in the "Insert" tab of PPT2007 main interface, click the "Picture" button in the toolbar, and import some pictures of leaves in PNG format that you have prepared, and put them on the left side of the slide preview area.
Step 2: Select any leaf picture in PNG format imported from the left side of the slide preview area, and then click the "Custom Animation" button in the "Animation" tab of the main interface to bring up the "Custom Animation" panel; Then click the "Add Effect" button in the panel, select "Action Path → Draw Custom Path → Arbitrary Polygon" and draw a trajectory line in the slide preview window (as shown in Figure 2a) to add an animation special effect of arbitrary polygon to the leaf picture; Then change the animation-related "Start" parameter to "Before" and the speed parameter to "Slow" in the "Custom Animation" panel (as shown in Figure 2, B and C); Finally, double-click the animation option in Figure 2, and d open the timing tab of the custom path dialog box, and modify the delay parameter to 1. 1 sec.
Step 3: imitate the operation of step 2, first select the leaf picture to which any polygon animation special effect has been added, click the Add Special Effect button, select Emphasis → Tuo Spiral, add a Tuo Spiral animation special effect to the selected leaf picture, and modify the start parameter to "before" and the speed parameter to "2.5 seconds"; Select this leaf image again, click the Add Effect button, and select Enter → Rotate to add a rotating animation effect. Finally, just change the start parameter of this animation effect to Before and the speed parameter to 2.5 seconds.
After the above steps are completed, the defoliation effect of the first leaf in the slide has been completed, and then the operations in the second and third steps are repeated to add defoliation effect to other leaf pictures imported into the slide. After adding the defoliation effects of all the leaves in the slide, press F5 to preview the final defoliation effects, as shown in Figure 3. How about watching the leaves fall on the slide in Figure 3? Did it work well? Teachers with this need may wish to give it a try.